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Abstract Energy consumption plays a dominant role in the technical and economic indicators of pipeline operation, and is greatly influenced by operation schemes. However, the conventional energy consumption model is often analyzed from the perspective of "energy" in the process of optimization without addressing the issue of energy quality. Based on energy quality, this paper analyzes exergy loss and exergy efficiency of every component of the crude oil pipeline transportation system. The expression of the exergy loss is determined and the mathematical model of the pipeline transportation system is established with the optimization objective of minimizing the total exergy loss of the system, which is combined the two optimization algorithms of genetic algorithm and multi-objective programming. Using one external oil pipeline in northeast China as an example, the model is used to do hierarchical optimization for the equipment arrangement and operation parameters of each station in the pipeline transportation system. The results found that the total oil transportation cost and the total exergy loss of the pipeline transportation system after optimization have seen an obvious improvement in the effective utilization of energy when compared to pre-optimized levels. The purpose of reducing the operation energy consumption and exergy loss of the system as well as each subsystem simultaneously has been achieved, and the theoretical basis is provided for the energy consumption optimization of oil pipeline transportation system operations. [ABSTRACT FROM AUTHOR]

With the rapid development of crude oil reserves, energy consumption in heating increases gradually, so it is necessary to study heating effect and energy utilization. In this paper, a theoretical model of coil heating process for large floating roof crude oil tank is established, with dynamic thermal environment and variable physical parameters of oil products taken into consideration comprehensively. The influence mechanism of coil structure on the coupling characteristics of heat transfer and flow of crude oil during heating process is revealed. On this basis, the heating effect of crude oil in storage tank is evaluated from the point of view of time and space respectively. Simultaneously, the properties of energy and its quality are both considered, the effective energy utilization efficiency of crude oil in storage tank during heating process is analyzed, and an optimization method for heating coil of tank oil is proposed. The results show that the temperature of oil products in the center and bottom of the tank increases linearly with the influence of heat sources, and the temperature of oil products at the roof and wall of the tank is greatly affected by the dynamic thermal environment, which is showing a change regulation of fluctuating pattern. The heating effect is greatly affected by coil length. The increase of coil length can obviously improve the flow structure of crude oil in the tank. A larger eddy structure can be formed in a shorter period of time, which can increase the heating rate of crude oil and further reduce the non-uniformity of temperature field. However, effective energy efficiency is greatly affected by coil diameter. The increase of coil diameter increases the convective heat transfer coefficient between coil and crude oil, which promotes crude oil to absorb heat more easily from heat sources and improves the effective utilization of energy and exergy. Therefore, the heating effect and effective energy utilization of oil coil can be further optimized by changing the length and diameter of coil. Relevant research results can provide theoretical and technical support for improving the utilization efficiency of reserve energy and reducing the cost of reserve energy consumption. Image 1096075 • The temperature of oil in tank center and bottom is increasing affected by heat source. • The temperature of oil at tank roof and wall fluctuates with dynamic thermal environment. • An optimization method on the basis of heating effect and effective energy is proposed. • Coil length can obviously improve the flow structure of crude and enhance heating effect. • Coil diameter can strengthen convective heat transfer process and enhance energy efficiency. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The heat flow coupling characteristics are revealed in the crude oil heating process. • The tank steam coil heating process has been divided into four stages. • The variations of crude oil temperature and flow field heated by different coils have been analyzed. • The heating effect evaluation indexes in the storage tank heating process have set up. Abstract Considering the factors such as ambient temperature, solar radiation, heating steam pressure and physical properties of oil products, a theoretical model for heating process of large floating roof tank coil is established. The numerical solution technology of the crude oil temperature field and flow field is studied to reveal the coupling characteristics of crude oil heat transfer and flow during the storage tank heating process. Furthermore, the influence law of different coil structures on the temperature field and flow field during the crude oil heating process is discussed. On this basis, the evaluation indexes of the heating effect on the crude oil storage tank is set up, which are combined with heating rate and uniform degree of temperature field. The results show that according to variations of crude oil flow field in the tank, the tank steam coil heating process has been divided into four stages including natural convection formation, small vortex formation, large vortex formation and large vortex development. The coil structures have great influence on the temperature field and the flow field of the crude oil tank. The vertical structure and the stereoscopic structure coils will form a certain thickness low temperature zone at the tank bottom during heating process, but the serpentine structure coil will form a heated dead zone at vertex angle and base corner of the tank where area is relatively small. On this basis, comparing the heating effect of the three kinds of coils, it is found that the heating rate of serpentine structure coil is the fastest and more stable. The uniform degree of temperature field is affected by the oil liquid level. Environmental temperature and other factors have little effect and the best heating effect. [ABSTRACT FROM AUTHOR]

Challenges in assessing hepatitis B virus (HBV)-specific T cell immunity as an immunological biomarker still remain in chronic hepatitis B (CHB), such as the requirement of large quantities of cells. This study aims to conveniently assess HBV-specific T cells immunity in chronic HBV infected patients. We obtained T cell receptor β chains (TCRβs) from public databases and six acute hepatitis B patients to establish an HBV-specific TCRβs dataset. For some TCRs from one acute patient, their specificities and epitopes were verified. The potential HBV-specific TCRβs from CHB patients were analyzed using GLIPH2 and established dataset. By analyzing two antiviral therapy cohorts including 42 CHB patients, we showed that individuals with better therapy response may depend more on newly emerging potential HBV-specific TCRβs. In a cross-sectional study containing 207 chronic HBV infected patients, the results exhibited that the characteristics of potential HBV-specific clusters were divergent between CHB and hepatocellular carcinoma patients. Our strategy could profile potential HBV-specific TCRβ repertoire using a small blood sample, which will complement traditional methods for assessing the HBV-specific T cell immunity. • A strategy for profiling the potential HBV-specific TCRβ repertoire using a small blood sample. • Chronic hepatitis B patients with better response to therapy depend more on new TCR. • Different HBV-specific TCRβ clusters characteristics between patients with chronic hepatitis B and hepatocellular carcinoma. [ABSTRACT FROM AUTHOR]